Physicochemical and Functional Properties of Salt-Extractable Proteins From Chicken Breast Muscle Deboned After Different Post-mortem Holding Times1

Abstract

Physicochemical and functional properties of chicken breast muscle samples and their salt-extractable proteins were investigated as a function of increasing post-mortem storage time at abovefreezing temperature prior to deboning and further processing. Functional properties, including water binding capacity, emulsifying capacity and thermally-induced gelation, were generally poorer after 2 days of storage, compared to no storage (0 day). After 7 days of storage, functionality improved significantly, and in most cases did not differ (P>0.05) from functionality at 0 day. No significant differences (P>0.10) were observed for pH after different storage times, but salt-extractable protein content of the chicken mince was higher at 7 days than at 0 or 2 days. Salt-extracted proteins from 7 day samples had lower solubility and higher hydrophobicity, while dispersibility and sulfhydryl group content did not differ compared to 0 and 2 day samples. On the other hand, the exposed hydrophobicity of proteins after heat treatment was lower at 7 days than at 0 or 2 days. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated some changes in the myosin and troponin components in the extracts from different post-mortem storage times.